Worksheet Overview

QUESTION 1 of 10

Hi code detective, the puzzles are coming in thick and fast! Are you ready to try something new? These sequences involve both letters and numbers! The letters and numbers are joined together in a special order.

Here is the alphabet for you to use as a reference:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Look at the following letter and number pair sequence:

A1 is to B2 as C3 is to ______?

First, we need to work out how the first letter becomes the second letter.

The letters are moving one place to the right in the alphabet.

Now we need to work out how the first number becomes the second number. This happens by adding one each time.

So we need to add one letter to C and one number to 3 to get the missing pair of D4.

So the answer is:

A1 is to B2 as C3 is to D4.

Let’s try another:

C4 is to E5 as F7 is to ______?

First, we need to work out how the first letter becomes the second letter.

The letters are moving two places to the right in the alphabet.

Now we need to work out how the first number becomes the second number. This happens by adding one each time.

So we need to add two letters to F and one number to 7 to get the missing pair of H8.

So the answer is:

C4 is to E5 as F7 is to H8.

In this activity, you will need to be a sequence superstar to complete the number and letter pairs.

Pssstt!! Here’s a handy hint to help you reach superstar status:

Remember to use the alphabet line to help you work out the code.

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

3 is to 4 as 5 is to ______ ?

Use your detective skills to work out the special sequence and find the missing number.

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

5 is to 7 as 9 is to ______ ?

Use your detective skills to work out the special sequence and find the missing number.

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

12 is to 14 as 20 is to ______ ?

Use your detective skills to work out the special sequence and find the missing number.

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

23 is to 26 as 14 is to ______ ?

Use your detective skills to work out the special sequence and find the missing number.

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

10 is to 8 as 12 is to ______ ?

Use your detective skills to work out the special sequence and find the missing number.

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

5 is to 10 as 15 is to ______?

Use your detective skills to work out the special sequence and find the missing number.

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

45 is to 46 as 38 is to ______?

Use your detective skills to work out the special sequence and find the missing number.

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

19 is to 16 as 34 is to ______ ?

Use your detective skills to work out the special sequence and find the missing number.

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

51 is to 49 as 19 is to ______?

Use your detective skills to work out the special sequence and find the missing number.

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

88 is to 91 as 45 is to ______?

Use your detective skills to work out the special sequence and find the missing number.

ANSWERS

Question 1

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

3 is to 4 as 5 is to ______ ?

Use your detective skills to work out the special sequence and find the missing number.

CORRECT ANSWER

6

EDDIE SAYS

Hi there, detective! The sequence here is add one. So 5 + 1 = 6.
Top tip: Work out the sequence in the first group. Then follow this same pattern to find the missing number in the second group.

ANSWERS

Question 2

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

5 is to 7 as 9 is to ______ ?

Use your detective skills to work out the special sequence and find the missing number.

CORRECT ANSWER

11

EDDIE SAYS

How did you get on? The sequence is to add two. So 9 + 2 = 11.

ANSWERS

Question 3

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

12 is to 14 as 20 is to ______ ?

Use your detective skills to work out the special sequence and find the missing number.

CORRECT ANSWER

22

EDDIE SAYS

Getting the hang of it? The sequence here is to add two. So 20 + 2 = 22. Great!

ANSWERS

Question 4

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

23 is to 26 as 14 is to ______ ?

Use your detective skills to work out the special sequence and find the missing number.

CORRECT ANSWER

17

EDDIE SAYS

Brilliant effort! The sequence here is to add three. So 14 + 3 = 17.

ANSWERS

Question 5

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

10 is to 8 as 12 is to ______ ?

Use your detective skills to work out the special sequence and find the missing number.

CORRECT ANSWER

10

EDDIE SAYS

We are moving backwards this time! The sequence is to subtract two. So 12 - 2 = 10.

ANSWERS

Question 6

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

5 is to 10 as 15 is to ______?

Use your detective skills to work out the special sequence and find the missing number.

CORRECT ANSWER

20

EDDIE SAYS

Did you find the missing number? The sequence this time is to add five. So 15 + 5 = 20.

ANSWERS

Question 7

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

45 is to 46 as 38 is to ______?

Use your detective skills to work out the special sequence and find the missing number.

CORRECT ANSWER

39

EDDIE SAYS

Did you work it out and locate the numbers? The sequence is to add one. So 38 + 1 = 39.

ANSWERS

Question 8

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

19 is to 16 as 34 is to ______ ?

Use your detective skills to work out the special sequence and find the missing number.

CORRECT ANSWER

31

EDDIE SAYS

This one is a bit more tricky! The sequence here is to take away three. So 34 - 3 = 31.

ANSWERS

Question 9

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

51 is to 49 as 19 is to ______?

Use your detective skills to work out the special sequence and find the missing number.

CORRECT ANSWER

17

EDDIE SAYS

The sequence is to subtract two. So 19 - 2 = 17.
Let's take a look at the last question in this activity!

ANSWERS

Question 10

Here are two groups of numbers. Each group follows the same special sequence, but with different numbers.

88 is to 91 as 45 is to ______?

Use your detective skills to work out the special sequence and find the missing number.

CORRECT ANSWER

48

EDDIE SAYS

The sequence this time is to add three. So 45 + 3 = 48.
Fantastic sequencing work. All the missing numbers have been found. Hope to see you again soon for another fun activity!

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